Internal-combustion-engine suspension



March 24 1925. 1,530,550 L C. FRE EMAN INTERNAL COMBUSTION ENGINE SUSPENSION Filed Feb. '7, 1924 "fi i "will,

INVENTOR. J ye/761' f /21472 ALTORNEY.

' of the city of Detroit, county of Wayne, and

Patented Mar. 24, 1925.

PATENT OFFICE.

LOWELL C. FREEMAN, 0F DETROIT, MICHIGAN.

INTERNAL-COMBUSTION-ENGINE SUSPENSION.

Application filed February 7, 1924. Serial No. 691,322.

To all whom it may com-em: Be it known that I, Lownm. FREEMAN, a citizen of the United States, and resident State of Michigan, have invented certain new and useful Improvements in Internal- .Combustion-Engine Suspensions, of which the following is a specification.

My invention has to do primarily with internal combustion engines of the four-cylinder type although it may be adapted to engines of the eight-cylinder type with equally as good results.

The primary object of my invention is to provide mountings for the engine so located and constructed as to damp out the vibration felt by the passengers of an auto mobile in which the engine is mounted, which vibration is caused by the unbalanced inertia forces of the reciprocating parts in the engine when running at certain speeds.

It is a well known fact that engines, particularly of the four-cylinder type, have certain speeds or periods when these unbalanced 2' inertia forces cause a vibration of and thru the frame of an automobile to the passengers riding in the same. This action is usually termed periods of vibration.

With the above and other objects in view my invention consists in the arrangement, combination and construction of the various parts of my improved devices as described in the specification, claimed in my claims and shown in the accompanying drawings in which:

Fig. 1 is a side elevation of an engine and the usual component assemblies secured thereto, and my improved mounting.

Fig. 2 is a front elevation of the same.

Fig. 3 is a detailed view showing partially in section the mounting means used on the front end of the motor.

I have shown a conventional engine assembly indicated generally as 5 having rear support members 6 and 7 adapted to be secured to an automobile frame and a flexible front support adapted to be secured to any suitable portion of a frame or an extension thereof, consisting of a leaf spring 8 secured to a nose 9 upon the front end of the engine by means of a ring 10 disposed around the nose 9, which ring is. provided with a flat plate like lower extremity 11. The spring 8 is disposed with its portion bearing against the bottom of the plate 11, and its bottom portion bearing against the top of a plate 12, which is secured to the plate 11 by means of bolts 13 secured in screw-threaded openings provided in the bottom of the plate 11.

It will be noted that the leaves of the spring 8 are loosely positioned over each other, except where they are drawn to ether at their centers by meansof the bots 13 and these bolts serve to prevent lateral displacement of the leaves. A screw-threaded bolt 14 is disposed thru the various leaves at approximately their center, which bolt also extends into the plate 11 and thru the plate 12 so as to prevent displacement of the leaves with relation to each other transversely. Limit stops may be provided or the spring attached to the chassis frame by bolts passing thru eyes formed in the main leaf.

The cylinders of the motor are indicated as 1,2, 3 and 4.

The resultant of the unbalanced inertia forces in the conventional engine acts in a plane midway between number 2 and 3 cylinders. The moment of this resultant force about a transverse horizontal axis thru the center of oscillation tends to rotate the motor about said axis, resulting in an approximately vertical movement at the front sup port and no tendency whatever for the center of oscillation to move relative to the car frame. This then is the place at which the rear motor supports 6 and 7 should be located and inasmuch as the centers of suspension and percussion are interchangeable, the center of percussion is thereby brought into the plane of the resultant of the un balanced inertia forces.

The provision of the leaf spring 8, with its natural amount of internal friction, at the front end of the motor then absorbs or damps out energy so as to prevent resonance or so called periods of vibration in the frame structure as its natural frequencies are approached or passed thru.

It is obvious therefore that the rear sup ports 6 and 7 must be so located as to receive substantially none of the movement or vibration caused by the unbalanced inertia forces in the motor and the leaf spring 8 must have a suficient amount of internal friction to prevent resonance or socalled periods of vibration.

I desire it to be understood that equally good results can be obtained by'the use of other damping means for the front support than a leaf spring without departing from the spirit of my invention. A resilient member having little or no internal friction may be used and the necemary friction introduced by other means, such as a shock absorber, for example, while theoretically the yielding support should be in the plane of the center of percussion, the errors introduced by its location at some other convenient point are ordinarily negligible.

While usually the best practice to be followed in, determining the point of rear motor support is to try various points of support to locate the point at which no such vibration from the motor is felt, which of course will vary with different motors, I shall nevertheless outline a simple method by which the point of support may be determined. This may be stated as follows:

1. Determine center of gravity of motor or power plant unit.

2. Suspend. the motor from the axis formed by the intersection of a plane intersecting at right angles the plane of the cylinder axes midway between the axes of #2 and #3 cylinders, with a plane contain: ing the center of graivity, said planes being at right angles to the lane containing the cylinder axes and to eac other.

3. Observe the time in seconds of a single oscillation of the motor so suspended, and com ute the length of the equivalent simple pen ulum by the formula 4. Locate the center of percussion by measuring the distance L in the direction of the center of gravity from the point determined by the intersection of the three planes. Arline in the plane of the center of gravity as defined above, parallel to the axis of suspension and passin thru the center of percussion will be the esired axis of the motor support which should theoretically be in the form of a trunnion. With the motor suspended from this new axis, the original axis of suspension then becomes the center of percussion and is in the plane of the resultant of the unbalanced inertia forces of the reciprocating parts.

Practically the location and method of attachment of the rear support to the frame is susceptible of slight modification, but for maximum results the ideal should be approached as closely as structural considerations will permit.

I desire it to be understood that various changes may be made in thearrangement,

combination and construction of the variousparts of my improved devices without departing from the spirit of my invention, and it is my intention to cover by my claims such changes as may be reasonably included within the scope thereof.

I further desire it to be understood that the words engine and motor as used herein are synonymous and that they may include the usual transmission assembly port being adapted to absorb said vibra- .t1ons.

v 2. An internal combustion engine ada ted to be supported by a frame, saidengine aving support members located at a point thereon substantiallyfree from engine vibration caused by the unbalanced inertia. forces therein and a cushioning support located at a point thereon where said vibrations are manifested, said support being tadapted to substantially absorb said vibraion.

3. The method of suspending an internal combustion engine which consists in so positioning a support thereon that the center of percussion of the unit falls in the plane of the resultant of the unbalanced inertia forces and positioning a vibration or energy absorbing element at another point thereon between said engine and the element by which it is supported.

4. The method of supporting an internal combustion engine which consists in so positioning a rear support for the engine and its attached power transmission elements that the center of percussion of the unit falls in the plane of the resultant of the unbalanced inertia forces and interposing as a front support, between the. engine and its supporting element, a structure having a substantial amount of internal friction.

5. An internal combustion engine having a rear support located at a point thereon substantially free from. engine vibration caused by the unbalanced inertia forces therein and a front support com rising a multiple leaf semi-elliptic spring aving a substantial amount of internal friction.

3. A front engine support comprising a. plurality of semi elliptic spring leaves Joined together solely at approximately their centers by members extending at the 5 sides thereof and attached to said engine and a member extending thru them and into a portion of said engine.

7. A front engine support comprising a lurality of semi-elliptic spring leava 10 Joined together solely at approximately their centers y members extending sides thereof and attached to sai at the and a member extending thru them and into a portion of said engine, said first mentioned members acting to'prevent lateral displacement of the leaves and saidsecond member acting to thereof,

prevent transverse displacement LOWELL o... FREEMAN.

en'e 

